dcigettext.c

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/* Implementation of the internal dcigettext function.
   Copyright (C) 1995-1999, 2000, 2001 Free Software Foundation, Inc.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software Foundation,
   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

/* Tell glibc's <string.h> to provide a prototype for mempcpy().
   This must come before <config.h> because <config.h> may include
   <features.h>, and once <features.h> has been included, it's too late.  */
#ifndef _GNU_SOURCE
#define _GNU_SOURCE    1
#endif

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <sys/types.h>

#if defined HAVE_ALLOCA_H
#include <alloca.h>
#else
#ifdef _AIX
#pragma alloca
#else
#ifndef HAVE_ALLOCA
void *alloca(size_t size);
#endif
#endif
#endif

#include <errno.h>
#ifndef errno
extern int errno;
#endif

#include <stddef.h>
#include <stdlib.h>

#include <string.h>

#if defined HAVE_UNISTD_H
#include <unistd.h>
#endif

#if defined HAVE_SYS_PARAM_H
#include <sys/param.h>
#endif

#ifdef HAVE_MALLOC_H
#include <malloc.h> /* Needed for alloca() on MingW/Win32 */
#endif

#include "elinks.h"

#include "intl/gettext/gettextP.h"
#include "intl/gettext/libintl.h"
#include "intl/gettext/hash-string.h"
#include "util/string.h"

/* Amount to increase buffer size by in each try.  */
#define PATH_INCR 32

/* The following is from pathmax.h.  */
/* Non-POSIX BSD systems might have gcc's limits.h, which doesn't define
   PATH_MAX but might cause redefinition warnings when sys/param.h is
   later included (as on MORE/BSD 4.3).  */
#if defined _POSIX_VERSION || defined HAVE_LIMITS_H
#include <limits.h>
#endif

#ifndef _POSIX_PATH_MAX
#define _POSIX_PATH_MAX 255
#endif

#if !defined PATH_MAX && defined _PC_PATH_MAX
#define PATH_MAX (pathconf ("/", _PC_PATH_MAX) < 1 ? 1024 : pathconf ("/", _PC_PATH_MAX))
#endif

/* Don't include sys/param.h if it already has been.  */
#if defined HAVE_SYS_PARAM_H && !defined PATH_MAX && !defined MAXPATHLEN
#include <sys/param.h>
#endif

#if !defined PATH_MAX && defined MAXPATHLEN
#define PATH_MAX MAXPATHLEN
#endif

#ifndef PATH_MAX
#define PATH_MAX _POSIX_PATH_MAX
#endif

/* Pathname support.
   IS_ABSOLUTE_PATH(P)  tests whether P is an absolute path.  If it is not,
                        it may be concatenated to a directory pathname.
   IS_PATH_WITH_DIR(P)  tests whether P contains a directory specification.
 */
#if defined _WIN32 || defined __WIN32__ || defined __EMX__ || defined __DJGPP__
  /* Win32, OS/2, DOS */
#define HAS_DEVICE(P) (isasciialpha((P)[0]) && (P)[1] == ':')
#define IS_ABSOLUTE_PATH(P) (dir_sep((P)[0]) || HAS_DEVICE (P))
#define IS_PATH_WITH_DIR(P) (strchr (P, '/') || strchr (P, '\\') || HAS_DEVICE (P))
#else
  /* Unix */
#define IS_ABSOLUTE_PATH(P) dir_sep((P)[0])
#define IS_PATH_WITH_DIR(P) strchr (P, '/')
#endif

/* XPG3 defines the result of `setlocale (category, NULL)' as:
   ``Directs `setlocale()' to query `category' and return the current
     setting of `local'.''
   However it does not specify the exact format.  Neither do SUSV2 and
   ISO C 99.  So we can use this feature only on selected systems (e.g.
   those using GNU C Library).  */
#if (defined __GNU_LIBRARY__ && __GNU_LIBRARY__ >= 2)
#define HAVE_LOCALE_NULL
#endif

/* This is the type used for the search tree where known translations
   are stored. */
struct known_translation_t {
	/* Domain in which to search.  */
	unsigned char *domainname;

	/* The category.  */
	int category;

	/* State of the catalog counter at the point the string was found.  */
	int counter;

	/* Catalog where the string was found.  */
	struct loaded_l10nfile *domain;

	/* And finally the translation.  */
	const unsigned char *translation;
	size_t translation_length;

	/* Pointer to the string in question.  */
	unsigned char msgid[1];
};

/* Root of the search tree with known translations.  We can use this
   only if the system provides the `tsearch' function family.  */
#if defined HAVE_TSEARCH
#include <search.h>

static void *root;

/* Function to compare two entries in the table of known translations.  */
static int transcmp(const void *p1, const void *p2);


static int
transcmp(const void *p1, const void *p2)
{
	const struct known_translation_t *s1;
	const struct known_translation_t *s2;
	int result;

	s1 = (const struct known_translation_t *) p1;
	s2 = (const struct known_translation_t *) p2;

	result = strcmp(s1->msgid, s2->msgid);
	if (result == 0) {
		result = strcmp(s1->domainname, s2->domainname);
		if (result == 0)
			/* We compare the category last (though this is the cheapest
			   operation) since it is hopefully always the same (namely
			   LC_MESSAGES).  */
			result = s1->category - s2->category;
	}

	return result;
}
#endif

/* Name of the default domain used for gettext(3) prior any call to
   textdomain(3).  The default value for this is "messages".  */
const unsigned char _nl_default_default_domain__[] = "messages";

/* Value used as the default domain for gettext(3).  */
const unsigned char *_nl_current_default_domain__ = _nl_default_default_domain__;

/* Contains the default location of the message catalogs.  */
const unsigned char _nl_default_dirname__[] = LOCALEDIR;

/* Contains application-specific LANGUAGE variation, taking precedence to the
 * $LANGUAGE environment variable.  */
unsigned char *LANGUAGE = NULL;

/* List with bindings of specific domains created by bindtextdomain()
   calls.  */
struct binding *_nl_domain_bindings__;

/* Prototypes for local functions.  */
static unsigned char *plural_lookup(struct loaded_l10nfile * domain,
			   unsigned long int n,
			   const unsigned char *translation,
			   size_t translation_len);
static unsigned long int plural_eval(struct expression * pexp,
				     unsigned long int n);
static const unsigned char *category_to_name(int category);
static const unsigned char *guess_category_value(int category,
					const unsigned char *categoryname);

/* For those loosing systems which don't have `alloca' we have to add
   some additional code emulating it.  */
#ifdef HAVE_ALLOCA
/* Nothing has to be done.  */
#define ADD_BLOCK(list, address)	/* nothing */
#define FREE_BLOCKS(list)	/* nothing */
#else
struct block_list {
	void *address;
	struct block_list *next;
};
#define ADD_BLOCK(list, addr)						      \
  do {									      \
    struct block_list *newp = (struct block_list *) malloc(sizeof(*newp));    \
    /* If we cannot get a free block we cannot add the new element to	      \
       the list.  */							      \
    if (newp != NULL) {							      \
      newp->address = (addr);						      \
      newp->next = (list);						      \
      (list) = newp;							      \
    }									      \
  } while (0)
#define FREE_BLOCKS(list)						      \
  do {									      \
    while (list != NULL) {						      \
      struct block_list *old = list;					      \
      list = list->next;			      			\
      free (old->address); 						\
      free (old);							      \
    }									      \
  } while (0)
#undef alloca
#define alloca(size) (malloc (size))
#endif /* have alloca */

typedef unsigned char transmem_block_t;

/* Checking whether the binaries runs SUID must be done and glibc provides
   easier methods therefore we make a difference here.  */
#ifndef HAVE_GETUID
#define getuid() 0
#endif

#ifndef HAVE_GETGID
#define getgid() 0
#endif

#ifndef HAVE_GETEUID
#define geteuid() getuid()
#endif

#ifndef HAVE_GETEGID
#define getegid() getgid()
#endif

static int enable_secure;

#define ENABLE_SECURE (enable_secure == 1)
#define DETERMINE_SECURE \
  if (enable_secure == 0)						      \
    {									      \
      if (getuid () != geteuid () || getgid () != getegid ())		      \
	enable_secure = 1;						      \
      else								      \
	enable_secure = -1;						      \
    }

/* Look up MSGID in the DOMAINNAME message catalog for the current
   CATEGORY locale and, if PLURAL is nonzero, search over string
   depending on the plural form determined by N.  */
unsigned char *
dcigettext__(const unsigned char *domainname, const unsigned char *msgid1, const unsigned char *msgid2,
	   int plural, unsigned long int n, int category)
{
#ifndef HAVE_ALLOCA
	struct block_list *block_list = NULL;
#endif
	struct loaded_l10nfile *domain;
	struct binding *binding;
	const unsigned char *categoryname;
	const unsigned char *categoryvalue;
	unsigned char *dirname, *xdomainname;
	unsigned char *single_locale;
	unsigned char *retval;
	size_t retlen;
	int saved_errno;

#if defined HAVE_TSEARCH
	struct known_translation_t *search;
	struct known_translation_t **foundp = NULL;
	size_t msgid_len;
#endif
	size_t domainname_len;

	/* If no real MSGID is given return NULL.  */
	if (msgid1 == NULL)
		return NULL;

	/* If DOMAINNAME is NULL, we are interested in the default domain.  If
	   CATEGORY is not LC_MESSAGES this might not make much sense but the
	   definition left this undefined.  */
	if (domainname == NULL)
		domainname = _nl_current_default_domain__;

#if defined HAVE_TSEARCH
	msgid_len = strlen(msgid1) + 1;

	/* Try to find the translation among those which we found at
	   some time.  */
	search = (struct known_translation_t *)
		alloca(offsetof(struct known_translation_t, msgid) + msgid_len);

	memcpy(search->msgid, msgid1, msgid_len);
	search->domainname = (unsigned char *) domainname;
	search->category = category;

	foundp = (struct known_translation_t **) tfind(search, &root, transcmp);
	if (foundp != NULL && (*foundp)->counter == _nl_msg_cat_cntr) {
		/* Now deal with plural.  */
		if (plural)
			retval = plural_lookup((*foundp)->domain, n,
					       (*foundp)->translation,
					       (*foundp)->translation_length);
		else
			retval = (unsigned char *) (*foundp)->translation;

		return retval;
	}
#endif

	/* Preserve the `errno' value.  */
	saved_errno = errno;

	/* See whether this is a SUID binary or not.  */
	DETERMINE_SECURE;

	/* First find matching binding.  */
	for (binding = _nl_domain_bindings__; binding != NULL;
	    binding = binding->next) {
		int compare = strcmp(domainname, binding->domainname);

		if (compare == 0)
			/* We found it!  */
			break;
		if (compare < 0) {
			/* It is not in the list.  */
			binding = NULL;
			break;
		}
	}

	if (binding == NULL)
		dirname = (unsigned char *) _nl_default_dirname__;
	else if (IS_ABSOLUTE_PATH(binding->dirname))
		dirname = binding->dirname;
	else {
		/* We have a relative path.  Make it absolute now.  */
		size_t dirname_len = strlen(binding->dirname) + 1;
		size_t path_max;
		unsigned char *ret;

		path_max = (unsigned int) PATH_MAX;
		path_max += 2;	/* The getcwd docs say to do this.  */

		for (;;) {
			dirname = (unsigned char *) alloca(path_max + dirname_len);
			ADD_BLOCK(block_list, dirname);

			errno = 0;
			ret = getcwd(dirname, path_max);
			if (ret != NULL || errno != ERANGE)
				break;

			path_max += path_max / 2;
			path_max += PATH_INCR;
		}

		if (ret == NULL) {
			/* We cannot get the current working directory.  Don't signal an
			   error but simply return the default string.  */
			FREE_BLOCKS(block_list);
			errno = saved_errno;
			return (plural == 0 ? (unsigned char *) msgid1
				/* Use the Germanic plural rule.  */
				: n == 1 ? (unsigned char *) msgid1 : (unsigned char *) msgid2);
		}

		stpcpy(stpcpy(strchr(dirname, '\0'), "/"), binding->dirname);
	}

	/* Now determine the symbolic name of CATEGORY and its value.  */
	categoryname = category_to_name(category);
	categoryvalue = guess_category_value(category, categoryname);

	domainname_len = strlen(domainname);
	xdomainname = (unsigned char *) alloca(strlen(categoryname)
				      + domainname_len + 5);
	ADD_BLOCK(block_list, xdomainname);

	stpcpy(mempcpy(stpcpy(stpcpy(xdomainname, categoryname), "/"),
		       domainname, domainname_len), ".mo");

	/* Creating working area.  */
	single_locale = (unsigned char *) alloca(strlen(categoryvalue) + 1);
	ADD_BLOCK(block_list, single_locale);

	/* Search for the given string.  This is a loop because we perhaps
	   got an ordered list of languages to consider for the translation.  */
	while (1) {
		/* Make CATEGORYVALUE point to the next element of the list.  */
		while (categoryvalue[0] != '\0' && categoryvalue[0] == ':')
			++categoryvalue;
		if (categoryvalue[0] == '\0') {
			/* The whole contents of CATEGORYVALUE has been searched but
			   no valid entry has been found.  We solve this situation
			   by implicitly appending a "C" entry, i.e. no translation
			   will take place.  */
			single_locale[0] = 'C';
			single_locale[1] = '\0';
		} else {
			unsigned char *cp = single_locale;

			while (categoryvalue[0] != '\0'
			       && categoryvalue[0] != ':')
				*cp++ = *categoryvalue++;
			*cp = '\0';

			/* When this is a SUID binary we must not allow accessing files
			   outside the dedicated directories.  */
			if (ENABLE_SECURE && IS_PATH_WITH_DIR(single_locale))
				/* Ingore this entry.  */
				continue;
		}

		/* If the current locale value is C (or POSIX) we don't load a
		   domain.  Return the MSGID.  */
		if (strcmp(single_locale, "C") == 0
		    || strcmp(single_locale, "POSIX") == 0) {
			FREE_BLOCKS(block_list);
			errno = saved_errno;
			return (plural == 0 ? (unsigned char *) msgid1
				/* Use the Germanic plural rule.  */
				: n == 1 ? (unsigned char *) msgid1 : (unsigned char *) msgid2);
		}

		/* Find structure describing the message catalog matching the
		   DOMAINNAME and CATEGORY.  */
		domain = _nl_find_domain(dirname, single_locale, xdomainname,
					 binding);

		if (domain != NULL) {
			retval = _nl_find_msg(domain, binding, msgid1, &retlen);

			if (retval == NULL) {
				int cnt;

				for (cnt = 0; domain->successor[cnt] != NULL;
				    ++cnt) {
					retval = _nl_find_msg(domain->
							      successor[cnt],
							      binding, msgid1,
							      &retlen);

					if (retval != NULL) {
						domain = domain->successor[cnt];
						break;
					}
				}
			}

			if (retval != NULL) {
				/* Found the translation of MSGID1 in domain DOMAIN:
				   starting at RETVAL, RETLEN bytes.  */
				FREE_BLOCKS(block_list);
				errno = saved_errno;
#if defined HAVE_TSEARCH
				if (foundp == NULL) {
					/* Create a new entry and add it to the search tree.  */
					struct known_translation_t *newp;

					newp = (struct known_translation_t *)
						malloc(offsetof
						       (struct